Cold spray is an advanced surface repair process that is revolutionizing many industries. The process is most important when repairs need to be performed in situ. Cold spray uses gas to accelerate metal powders usually in the 5 um to 100 um to supersonic speeds. As the accelerated particles hit the substrate material, they plastically deform and deposit onto the substrate to create bonds.
Many materials can be deposited this way (Aluminum, Titanium, etc). Manufacturers have developed portable devices that can be used for these purposes. They are composed of a nozzle that a trained user points to the area where deposition is desired. The process is similar to painting or coating a surface, with the main difference being that significant buildup can be applied to repair the surface. Currently, the user sprays in the locations where he/she perceives that the repair is needed. Often, a trigger-like mechanism is used in the nozzle to control the amount of particles being ejected.
General Electric (GE) researchers have developed an additive technology called “Cold Spray,” in which metal powders are sprayed, at high velocities, to build a part or add material to repair an existing part. Cold spray is part of GE's expanded additive manufacturing toolkit.
The technology was invented in Russia in the mid-80s, and today cold spray is mostly used for repair. The biggest application in the US is for the US army to repair helicopter parts that are made out of magnesium alloys. But most of the work being done today is soft, low temperature alloys, like copper, aluminum, and zinc. For GE, the challenge was to use this technology to produce high quality deposits made of high temperature Ni and Ti alloys. The Cold Spray technology GE has developed can be used for additive manufacturing to build 3D shapes, or repair existing metal construction without damaging or investing heavily in the core material.